In the near future an increasing demand for communication over wide distances, especially for example between continents or with subsea oil and gas processing equipment/consumers will be needed. Hence, infrastructures, like sea cables and connectors linking subsea cables and modules, e.g. subsea modules, like transformers, pumps etc., that are located and operated error proof subsea will be essential.
Electrical connectors, interconnects and feed-throughs or penetrators, respectively, are consider to be some of the most critical components in any electrical communication and/or power distribution system. They provide a rugged and reliable method for connecting and disconnecting electrical conductors and a means for penetrating barriers and bulkheads with said conductors. Often these connectors and penetrators are employed in remote and harsh environments, with one such remote, harsh environment being subsea.
Typically, such connectors may be used for interfacing electrical distribution equipment such as transformers, switchgear and variable speed drives with rotating equipment including pumps and compressors that are routinely used in the extraction of oil and gas resources. In addition, connectors may also be used for interfacing communication systems (including analogue, Ethernet and fibre optic systems) with sensors, actuators and the like, used in the control and monitoring of oil and gas production equipment.
Although generally very robust, any connection within a system where additional leak paths and complicated mechanical assemblies are introduced will inevitably be considered a ‘weak link.’ The integrity of a connector is further questioned where it is mateable (or dis-connectable) whilst subsea (i.e. fully submerged in sea water).
Moreover, these devices are often complex mechanical assemblies that are subject to pressure and temperature fluctuations as well as variable electrical stresses. Modes that could lead to the failure of a connector include, but are not limited to, ingress of water into the connector, contamination of the compensating media, incorrect mating (resulting in poor electrical contact/continuity), sudden temperature increases, de-mating whilst energized, significant pressure differentials from inside to outside the connector etc. The likelihood for many of these failure modes occurring increases over time as materials are aged, thermally and/or mechanically fatigued, electrically stressed or subject to other degradation mechanisms.
The remote location and relative inaccessibility of many of the world's oil and gas producing locations precludes visual inspection and on site monitoring, and for the same reasons, any sudden failures can cause expensive and time consuming interventions.
It is currently the practice to construct the devices so that they outlast a predefined time span and after this span is reached to replace the devices. Thus, the connector is replaced after a defined period, during a routine maintenance period or after failure. However, this often results in the replacement of totally functional and still reliable devices and thus increasing costs and service efforts. Furthermore, a sudden failure can occur any time during the predicted lifetime of the device what may result in catastrophic situations.